


the best things come in threes

by theinvisibledisaster



Series: 666 Fics [5]
Category: The 100 (TV)
Genre: Alternate Universe - Modern Setting, Bellamy as Zane, Best Friends, Clarke as Rikki, F/M, Friends to Lovers, Friendship/Love, Marper as Clewis, Mermaids, Time Skips, h2o au
Language: English
Status: Completed
Published: 2019-10-05
Updated: 2019-10-05
Packaged: 2020-11-24 12:46:54
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,528
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20907896
Author URL: https://archiveofourown.org/users/theinvisibledisaster/pseuds/theinvisibledisaster
Summary: The next day, Clarke had gotten caught in the garden sprinklers at the golf course and ended up lying on the green with something heavy instead of legs.When Emori tried to have a shower, she sprouted a tail and collapsed to the tiles.And Harper had to quit the swim-team, because every time she dove into the pool, she risked betraying their secret to the world, or at least her swim-coach.But they were managing it.or, the H2O AU that's been sitting on my laptop for over a year!





	the best things come in threes

**Author's Note:**

> [@carrieeve](https://carrieeve.tumblr.com/) picked H2O from my WIP list in my tumblr follower celebration, and it sort of spiraled out of control. I have no regrets. I hope you like it!!

Clarke had never meant to end up stuck on the island, let alone getting stuck with Harper and Emori - two girls she barely knew and had no intention to befriend - but there she was. Not only were they stranded, but Harper had somehow managed to fall down a hole and caught both their ankles as she slipped, bringing them down with her.

All she’d meant to do was rescue Harper from Bellamy and his friends and their stupid teasing, but when she stole his little dinghy and pulled up to give Harper a ride off the pier, she hadn’t noticed how low the petrol was. Emori had climbed onboard just as they were turning out towards the wide open ocean and the three of them had been so busy arguing about whether or not Bellamy deserved his boat back, that they didn’t notice when it stopped moving.

And then the weirdness started.

The surprisingly well-lit pool at the bottom of the cave had started glowing and bubbling.

And the next day, Clarke had gotten caught in the garden sprinklers at the golf course and ended up lying on the green with something heavy instead of legs.

When Emori tried to have a shower, she sprouted a tail and collapsed to the tiles.

And Harper had to quit the swim-team, because every time she dove into the pool, she risked betraying their secret to the world, or at least her swim-coach.

But they were managing it.

* * *

_“I want to tell Monty.”_

_They were in the Moon Pool, taking a break from studying._

_Emori thumped her head back against the rocks around the edge. “Harper, for the thousandth time, you can’t tell **anyone**.”_

_She huffed. “I’ve heard the spiel, I’m just saying, I think he could help us. He’s really smart, and he’s into that occult stuff.”_

_“Mermaids aren’t occult.” Clarke said idly, barely paying attention to the argument, too busy thinking about all the places around the reef that she hadn’t had a chance to explore yet._

_“Whatever.” Harper pouted. “He’s my best friend, okay, I can’t keep something this big from him.”_

_“Try.” Emori said._

_“It’s not fair, it’s easy for you guys - you’re great at keeping secrets and Clarke-” She cut herself off._

_Clarke swirled her arm through the water. “Clarke doesn’t have anyone to tell. Is that what you were going to say?”_

_Harper turned pink. “Hey, I’m sorry, that’s not… I didn’t mean…”_

_“I know.” She said. Something caught her eye in the sand below, and she sunk to the bottom of the pool. She was still amazed at how clearly she could see underwater now. Closer, she could tell that the glint had come from a silver locket with a green gem set into the top. She plucked it from the sand and returned to the surface, where Harper and Emori were **still** arguing._

_“He won’t tell anyone.”_

_“You can’t promise that.”_

_Clarke glanced over at them. “Em’s right, even if he doesn’t tell anyone else, not telling Jasper would **kill him. **You really wanna do that to your best friend?”_

_She made a face at them both, but it seemed the argument was over for the moment._

_“What’s that?” Emori asked._

_“Present for you.” She said, tossing it through the air._

_She examined it, hooking the chain around her neck. “This looks antique. I wonder how it ended up here.”_

_“Could have washed up from a shipwreck. God knows there are enough of them around this island.” Harper suggested._

_Clarke hummed agreement._

_“Or maybe someone else knows about this place.”_

_“Not likely.” Emori said. “We had to fall in to find it.”_

_There was a clatter, and then a rock bounced down into the water with a plop. Clarke glanced up just in time to see someone lurch down the hole and into the cave, sprawling in a mess of limbs at the edge of the pool._

_“Speaking of.” Clarke deadpanned._

_The limbs rearranged themselves and suddenly Monty’s terrified face was staring back at them._

_**“Monty?!”** Harper gasped._

_“Uh. Guys. What’s going on?” He asked, eyes darting over all three of them._

_Emori groaned. “Guess you got your wish, Harp. We’re mermaids, genius.”_

_“Right.” He said slowly, still taking it in. “But… where do your legs go?”_

_Clarke frowned thoughtfully - that question hadn’t really occurred to her - and flicked her tail. “Not sure. You wanna help us figure it out?”_

_“Clarke!” Emori complained._

_“What? He’s in it now; we can hardly make him forget, and like Harper said, he’s smart and he’s interested in weird shit - this definitely qualifies.”_

_“How did you even find this place?” Harper asked._

_“I was looking for you. You said you went camping on the island with the girls, and I realised that there was no moon tonight and you might get lost, so I brought my GPS equipment to make sure you made it back safely. And then I fell down this crevice and… this.” He gestured at them. “Which, by the way, is so freaking cool.”_

_“Flattery will get you everywhere.” Harper teased._

_Was that a trick of the light or did Monty blush?_

_Emori was still all business. “But if you tell Jasper about this-”_

_“-I won’t.” He said, determined. “I swear.”_

_“I’m sold.” Clarke said, lounging against the side of the pool so she could bump fists with him. “Welcome to Mermaid Club, Green.”_

_Harper could barely contain her squeak of delight, and Monty beamed at her. “So, not to ask the obvious, but how the hell did this happen?”_

* * *

Clarke, who had previously prided herself on being a loner, now had two best friends that she would do anything for. Emori acted like a Straight A student while also being a vicious sneak thief who could get anything off anyone. And Harper was a badass who took up kickboxing the second she dropped swimming - something about putting the energy into worthwhile pursuits.

She wasn’t alone anymore.

They swam together every week, studied together at school, and she and Emori had spent the last few months plotting together to try and get Harper to realise that she was in love with her best friend - who was still the only other person who knew about their powers.

It took them what seemed like forever and a frankly _excessive_ amount of meddling, but they finally admitted their feelings to each other after the school dance. Monty hadn’t asked her, and Harper had ended up going with Miller, and Clarke had to remind Monty every five minutes that Miller was not remotely interested in Harper and only asked her as a friend. Finally, he cracked and asked her to dance, and Emori and Clarke sat to the side and watched them, grinning the whole time.

Even Bellamy had grown on her - drifting away from his douchey friends, breaking up with Echo, and generally becoming less of a dick.

During the dance, Emori snuck off to make out with Murphy in the cloakroom - and she really thought she was being subtle about it - and Clarke ended up sitting on her own, awash with happiness at the happiness of her friends.

Bellamy had sidled up to her, offering her an unopened can of coke and leaning on the table behind her with his usual charm and a sly, “Bored, Princess?”

She’d been ready to rebuff him, but it seemed like he just wanted to talk, and they ended up getting into a long discussion about their english teacher’s misunderstanding of Romeo and Juliet, until Bellamy noticed Jasper trying to spike the punch and slouched off to stop him. After that, Clarke had looked for him, only to see Harper and Monty making out on the dancefloor and rushing to find Emori and tell her. She didn’t see him again for the rest of the night.

But it had been a nice moment, while it lasted.

And during a full moon a few weeks later he’d even tried to help her when he found her surrounded by a ring of fire on the island.

* * *

_She was spinning out, anxiety taking over, and everything she touched was set alight._

_She’d only gone to the island to isolate herself, but even there she couldn’t keep anyone safe, because Bellamy appeared out of nowhere, evidently camping on the beach nearby._

_“Whoa, Princess, are you okay?” He asked, leaping over a flaming log to get to her. He reached out but the second he touched her skin, he hissed and leapt back. “Shit, Clarke, you’re burning up.”_

_“Leave me alone, Bellamy.” She muttered._

_“Have you noticed you’re surrounded by** fire**?” He pointed out. “What if I leave and you get caught in it?”_

_“I won’t.”_

_“You don’t know that, fire is fickle.”_

_“And if you stay, you could get burned too. Or suffocate on the smoke.” She sighed, rubbing her eyebrow tiredly. “Just go away.”_

_He made a show of settling further in next to her, planting himself on the ground and raising his eyebrows like he was waiting for her to fight back. She just rolled her eyes._

_“No argument? Really? Who are you and what have you done with Clarke?”_

_She didn’t say anything, just focussed on a piece of burning grass beside her, trying to pour all her overheating energy into it so Bellamy didn’t get hit. It burst into flames and burned out in seconds, leaving only ash and smoke behind._

_Bellamy blinked at it. “This island is so weird.”_

_“You’re telling me.”_

_“Seriously, Clarke, are you okay?” He asked, hand hovering over her shoulder like he wasn’t sure if he should touch her or not._

_She shrugged helplessly. “No.”_

_“Is there anything I can do?”_

_“No. I’m just… I don’t have anything left, you know? My dad’s gone, my mother is… dealing with things on her own, and I’m trying so hard, but everything’s just **too much**, all the time.”_

_“Don’t say that, what about Harper and Emori?”_

_She scoffed. “They don’t even like me, they’re just friends with me because-”_

_“Because?”_

_“Forget it.”_

_He shuffled closer, trying to catch her eye. “Look, I can’t speak for them, but from what I’ve seen, those girls **love **you. The three of you are practically attached at the hip, have been all year. I know you’re used to being on your own, but… you’ve got friends here, Princess.”_

_“And I suppose you’re one of those, are you?”_

_“If you want me to be.” He said, lying back on the leaves and staring at the stars._

_“Maybe.” She admitted, flopping back next to him and setting a twig alight with her fingers._

_He smiled up towards the sky. “Then it’s settled. As long as you’re risking death by sitting in the smoke, I’m sticking around. At least then you’re not dying alone.”_

_“You’re so dramatic.” She sighed._

_“I’m sorry, which one of us was sitting in a ring of fire and refused to leave?”_

_“Shut up.”_

* * *

They’d been friends ever since.

It was weird, how quickly he slotted into her life, how much he brightened her day simply by appearing at her desk, but she tried not to examine it too closely. She was finally in a place where she felt at home and _happy_. She had Harper and Emori, and she hung out with Monty whenever he was around, and she even had Bellamy Blake driving her home from school. It was almost perfect.

Naturally, it couldn’t last.

Things got a little complicated when he started hunting them down.

It was her own fault, really.

He capsized off the island where she _happened_ to be swimming and nearly drowned, and she - idiot that she was - decided to save him. She figured he was unconscious, but apparently not, if his sudden interest in siren lore was any indication.

He started carrying around old tomes filled with supposed siren and mermaid sightings, and compared old sketches to his own rudimentary drawings of what he thought he’d seen - which was luckily only the fin of her tail as she sped away. He even went back to the wreckage and dove to the bottom to investigate the boat, finding a huge dent in the door and, somewhat surprisingly, a locket on the ocean floor.

He’d run up to her the next day, locket in hand, and ranted about how that was a popular spot for shipwrecks and talking about how old the necklace was, and the whole time, all Clarke could think about was that it was identical to Emori’s, except that the gem was red.

When she told the girls about it, Emori suggested stealing it, but she told her not to. She didn’t want to make Bellamy even more suspicious than he already was.

She even started to pull back the more he talked about it, worried that he was going to find out, and terrified of what he’d do if he did.

It put a bit of a strain on their burgeoning friendship, especially when her friends found out.

“I’m telling you, Clarke, this is a bad idea.” Harper said from her place on Emori’s bed.

“I agree, in case you’re wondering.” Monty said.

“We weren’t.” Emori deadpanned, not even looking up from painting her nails, and he flipped the bird at her.

Clarke rolled her eyes. “Look, he doesn’t know it’s _us_ he’s hunting, he just thinks he’s hunting mermaids. He’s my friend, you can’t stop me from hanging out with him.”

“Is he though?”

“What’s that supposed to mean?”

“Nothing. Just that you seem awfully cosy with him lately.” Emori raised her eyebrow at her, like a challenge.

“Em, your family has been friends with his for years. His little sister hangs out with _your_ brother.” She pointed out. “Not to mention his best friend is your boyfriend.”

“Murphy is _not_ my boyfriend.”

Harper snorted. “Oh he _so_ is.”

“This isn’t fair, we’re supposed to be ganging up on Clarke!” She threw a makeup brush at her.

“Look, all we’re saying is that we think you should be _careful_.” Harper said placatingly. “What happens if he finds out that you’re the creature he’s been obsessing over for months?”

“The boy knows how to obsess.” Emori muttered.

“So do you, apparently.” Clarke said haughtily. “Look, I appreciate the concern, I really do, but he’s not going to find out. And if he does… we’ll just kill him.”

“I’ve got a boat, we could ambush him at sea.” Monty suggested, getting to his feet so he could grab a bag of pretzels off the shelf.

“And then I could feed him to the sharks.”

“Nice.” Monty high-fived her, grinning.

“Babe, you were supposed to be on _my_ side!” Harper said, batting her eyelashes.

“Oh right, sorry.” He returned to his place on the mattress beside her. “No, Clarke. Don’t have autonomy. Submit to the hivemind.”

Harper elbowed him, but she was looking at him with hearts in her eyes, shifting closer. “You’re the worst.”

“And I’m late.” Clarke said, checking her watch.

“And _I’m_ about to throw up, so I think I’ll come with you.” Emori said, springing to her feet and blowing on her nails as she followed Clarke out of the house. Before she shut her bedroom door she yelled through it, “If you two have sex on my bed I’m gonna sick Clarke’s sharks on you!”

They were halfway down the street when Emori caught Clarke’s arm. “Look, I like Bellamy. He’s a dick, but I like him. So if you think you know what you’re doing, then I trust you.”

Clarke paused. “...where did this sudden change of heart come from?”

Emori held out for barely a second before she cracked. “Okay, I _might_ be dating Murphy.”

Clarke cackled with laughter and started towards her car. “You don’t get out of being judged for that just because you forgive me for having a thing for Bellamy.”

“It was worth a shot!” Emori called after her.

* * *

Clarke always felt a little uncomfortable arriving at Bellamy’s place.

It was the kind of house she remembered living in as a child, but when her father died and her mother used the entire life insurance payout to fuel her addiction, they’d had to move into a smaller house. Then a smaller one. Then a caravan. But her mother had finally hit rock bottom and decided to look for help, and the best clinic for addiction was in the seaside city, so they moved. And she was glad they did - if they hadn’t, Clarke would never have ended up on the island with Harper and Emori.

Bellamy was the inverse - they’d started off with nothing, struggling through life, until Echo’s dad gave his mother a chance and funded her business idea. Suddenly their family had more money than they knew what to do with, and middle school Bellamy really let it go to his head. He became a massive douche - although Clarke had never seen him before that, she had it on Monty’s word that he used to be cool - and remained that way for a while.

Now, at least, he was turning it around again.

She let herself in and walked around to the back garden, finding him exactly where he always was; lying down in the shade beside his pool, a mojito in hand.

“That better be a virgin.” She said.

“No virgins in sight, Princess.” He didn’t even bother opening his eyes. “Unless Jasper’s around.”

“You’re supposed to be driving, dick.”

“I changed my mind.”

“Well, I didn’t.” She said, poking his leg with her foot. “I want to see the new superhero movie and you’re coming with me.”

“You’re cute when you’re bossy.”

“You’re cuter when you pay for my movie tickets.” She retorted.

He finally cracked an eye open, sighing as he sat up. Now that she was looking at him up close, she noticed how tired he appeared, and she longed to reach out and stroke the hair from his eyes. She was about to ask what was wrong when Bellamy got to his feet, standing so close that she had to crane her neck up to see him properly.

“Bellamy, what’s going on?”

“I figured something out.” He said, expression dark. “I was doing some research last night, trying to work out how mermaids could possibly go undetected if they live in the sea all the time, or why they’d even come to the surface at all, and then I realised… they must be able to come on land.”

Clarke swallowed. “That’s, uh, an interesting hypothesis, but last time I checked, mermaids still weren’t real.”

He stepped forward and she took a step back.

“I’m really sorry, Clarke.” He said, right before he took another step and she tumbled backwards into the pool.

She hit the water with a splash, and she was going to _kill_ him.

When she emerged, spluttering, he was crouching on the side, watching her intently, and she felt herself beginning to change. The water bubbled around her and the tail miracled into being, her nice blouse changing into the scaled bikini it always did. She glared up at him.

“I should have brought Monty’s boat.” She muttered.

“What?” He asked, not really listening, clearly too captivated by her tail.

“What the _hell_, Bellamy?!” She snapped, furious.

He cut his eyes up to her face. “Look, I’m sorry, but I just… I figured it out last night. All the weird things that have been happening with you and the girls lately, and how cagey Monty gets every time I ask him to help me look for mermaids, even though I _know_ he loves that mystical stuff - it just made sense.”

“So you thought you’d piss me off?”

“I knew you’d deny it if I accused you. I figured if I was wrong, you’d just be wet and assume I was messing with you, and if I was right-”

“-what, you’d finally be proven right? Well congratulations, Blake, you’ve succeeded.” She growled, and his face fell.

“Hey, I didn’t want to upset you.” He said, looking genuinely hurt at the prospect.

“Yeah, well, best laid intentions.” She folded her arms angrily.

He shook his head. “No, wait, listen; I’m not… I… Clarke, you’re a mermaid.”

“Really? I hadn’t noticed.”

“And I get that with how I’ve been talking lately might make you think that you couldn’t tell me about it.” He continued like she hadn’t said anything. “I’ve been obsessed with finding the mermaid who saved me, and I can see how that must have come across, but I never wanted to _catch_ you, I just wanted to _thank_ you.”

She felt her resolve slipping, and she tipped her chin up defiantly. “Who’s to say I’m the one who saved you?”

“So you’re _not_ the only one.” He grinned, and she cursed herself. “It’s Harper and Emori, right? You three can’t be as close as you are and not share a secret like that.”

She didn’t say anything.

“Clarke. I’m not coming after you. I swear.” He got down onto his knees, sitting on the edge but not touching the water. “Talk to me, Princess. Yell at me, tell me you hate me, tell me you never wanna speak to me again, just… say something.”

His eyes were earnest, pleading.

“You saved my life, Clarke.” He whispered.

“I never admitted to that.”

A relieved smile crossed his face. “But you did, right?”

Clarke gave in, swimming a little closer. “Yeah, dick, I did. And not a day goes by that I don’t regret it.”

He mock-glared at her.

“It’s not my fault you hit a reef, Bellamy. You’re lucky I was there.”

“Yeah. I am.” He said, serious.

“Please don’t thank me.” She muttered, suddenly feeling embarrassed, and he reached for her hand, seemingly not caring that hers was soaking wet.

He laced their fingers together and tugged her closer, right up to the edge of the pool. _“Thank you,_ Clarke.”

She smirked, and he realised what she was going to do a split second too late, eyes widening as she yanked his arm and dragged him into the water. He fell in with an enormous splash and came up spluttering and flicking his hair.

Clarke laughed at his unimpressed expression, but there was something behind it, something like determination, and she realised he’d planted his feet. She was half-expecting him to try and shove her underwater, or splash water at her, or something ridiculous like that, but instead, he slid his arms around her waist and pressed her to his chest.

She swallowed, not used to the close proximity, tail flicking anxiously.

Water was dripping off his lashes as he glanced between her eyes and her lips.

“I really like you.” He said quietly.

She shook her head. “You’re obsessed with mermaids. And you’re grateful. That’s different.”

“You’re right, it is different.” He said. “I liked you _long_ before you saved my life.”

His lips brushed hers, tentative, and she reacted immediately, hands finding his damp curls and tugging him closer as he kissed her more assuredly, palm sliding up her spine. When they broke apart, he pressed his forehead against hers and she kept her eyes closed, trying to hold onto the moment.

“Harper and Emori think this is a bad idea.”

It was the first thing that came into her head, and she felt him pull back a little, so she opened her eyes, only to find him appraising her thoughtfully.

“This, specifically? Because I’m really enjoying it.” He teased.

She pinched his shoulder. “What if they’re right?”

“They’re not.” He said. “I already told you, now that I know it’s you, I’m done hunting.”

“If you say anything about having already caught your fish, I’m going to feed you to my sharks.” She threatened, and he laughed, walking them backwards until her back was against the side.

“You’ve got nothing to worry about, Princess.”

She bit her lip. “You like me.”

“I like you.”

“For how long?”

“Pretty much since you moved to town.”

“But you were such a dick.” She said, and he ran a hand through his hair, sending water droplets everywhere.

“Don’t remind me. I was trying to be someone I’m not, to fit in with those rich kids, and all it did was make me hate myself.” His hand ended up on her neck, thumb stroking her jaw absentmindedly. “Murphy was the only friend I kept from when we had nothing, and when he told me he’d stop coming round if I kept acting like I did, I realised it must be bad.”

“Remind me to thank Murphy the next time I see him.”

“That probably won’t be for a while - he hasn’t left Emori’s place for like, two days.”

Clarke’s jaw dropped. “I _knew_ it.”

“So, now that we’ve settled that I’m not going to harpoon you or send you off to be dissected, do you wanna tell me how you managed to spring a tail? Did you cross an ancient god? Summon a water spirit? Splice a fish onto your bottom half?”

She snorted, splashing him. “Definitely the last one.”

“Hot.” He deadpanned, leaning in to kiss her again.

* * *

Being a mermaid had its perks.

On top of the obvious - like being able to hold your breath for an insanely long time, and the fact that dolphins and sharks seemed to gravitate towards you - it gave them access to a secret cave where they could spend time together with no-one else in sight.

Well.

Nearly no-one.

Bellamy opened the bag of doritos and offered Clarke one. She held up her wet hands in answer and he shrugged. “I can feed you.”

“Gross.” Emori muttered.

“Don’t you dare start, I’ve just watched you eating Murphy’s face for the last ten minutes.” Clarke retorted.

Murphy grinned. “Don’t tell me you didn’t love every second of it, Clarke.”

Monty held up his hands, quietening everybody. “Regardless of how gross it is to see Murphy kissing _anyone-”_

“-ooh, talk dirty to me-”

“-we’ve come a long way this last year. And I think that should be commemorated.” He pulled out a camera.

They slid into the pool with the girls, coupling up, and all six of them squished in close together, but Monty’s arms still weren’t long enough to get them in the shot. He sighed and set the timer, putting the camera on the edge.

“Say ‘reef sharks’!” Murphy said cheerily.

The camera flashed, but none of the boys got out of the pool, choosing to forgo the food in lieu of relaxing in the water with their mermaid girlfriends.

Monty checked the display, his arm slung around Harper’s shoulders, and she rested her head on his shoulder. She smiled. “That’s a nice one.”

“Definitely one for the facebook page.” He teased.

Clarke splashed him.

He looked over, shocked, and put the camera aside so he could splash her back.

Bellamy made a show of leaping in front of it like he was taking a bullet for her, and Harper fell about laughing. Emori pretended she didn’t care, but Clarke could see the smile tweaking at her lips.

Yeah.

It had been a pretty good year.

**Author's Note:**

> Thoughts?
> 
> Your kudos and comments make me happier than a mermaid in the water.


End file.
